This application is based on and claims the priority under 35 U.S.C. xc2xa7119 of German Patent Application 198 08 004.2, filed on Feb. 26, 1998, the entire disclosure of which is incorporated herein by reference.
The invention relates to a structural component forming a transmitter and a receiver for a bi-directional, wireless transmission of data carried by radiation energy particularly in the range of infrared radiation to and including ultraviolet radiation.
Such transceivers are currently used for data transmissions particularly with an infrared radiation carrier for which IRDA standards have been developed. The data transmission takes place optically from one point to another in accordance with the just mentioned standards, for example for remote controlled purposes. The firm Temic Semiconductor GmbH of Heilbronn, Germany markets such transceivers as Models TFDS 4000 or TFDS 6000 for various purposes. These transceivers have integrated components and features satisfying the IRDA (Infrared Data Association) standard.
One such transceiver is described in European Patent Publication EP 0,712,161 A1. An infrared transmitter or emitter is housed in a special housing and an infrared receiver or detector is arranged in the same housing in combination with an integrated circuit for signal processing and amplification. These three semiconductor chips for the emitter, the detector, and the processing circuit are supported on a conductor strip arrangement with at least three strip sections positioned in two planes extending perpendicularly to one another. This type of arrangement results in a structural grouping having very small housing dimensions particularly for use in a PCMCIA card for infrared communication in connection with personal computers.
The above conventional semiconductor structural component for bi-directional optical wireless transmissions however has certain drawbacks. For example, due to the small apertures of the lenses that are arranged in front of the detector chip and in front of the emitter chip, the optical transmitting and receiving power is rather low, whereby the transmission range of the optical data transmission is noticeably limited.
In view of the foregoing it is the aim of the invention to achieve the following objects singly or in combination:
to substantially increase the optical transmission and reception power for wireless optical transceivers operating with electromagnetic waves in the range of infrared to and including ultraviolet;
to construct the present transceiver, especially its housing, in such a way that a substantially larger lens aperture can be realized without requiring a larger housing for accommodating a larger lens or lenses;
to arrange the components of the transceiver in such a way in a housing that a thin housing can carry a thick lens or thick lenses;
to construct the housing of the transceiver in two but integral sections including a circuit and chip section and a lens section with the latter thicker than the former; and
to increase the lens diameter for an enlarged aperture and a correspondingly increased transmission and reception range while simultaneously optimally reducing the dimensions of a housing carrying the lens or lenses.
A transceiver according to the invention is characterized by the combination of the following features. A transceiver housing is divided into two sections, namely a flat section to house circuit components and a lens section for focussing or bundling radiation. An electrically conducting strip for supporting the circuit components including emitter/detector chips is mounted in the flat housing section and a lens or lenses are formed as integral parts of the second housing section. The electrically conducting strip is preferably a grid strip and has a first mounting plane on which a circuit such as an integrated circuit is mounted, and a second mounting plane carrying an emitter chip and a detector chip. Alternatively, the integrated circuit and the chips are mounted on the same mounting plane of the grid strip. The first housing section is flat and has two opposed surfaces extending in parallel to each other and are larger in area than the side surfaces of the first housing section. The second housing section has a spherical or hemispherical shape to form the lens or lenses having a directional optical axis. The diameter D of the hemisphere or sphere is substantially larger than the thickness d of the first housing section (D greater than d). Further, the optical lens axis of the hemisphere or sphere and a mounting plane of the transceiver are spaced from one another by a spacing xe2x80x9caxe2x80x9d in such a way that the surface of the hemisphere or sphere does not project outside both flat surfaces of the flat housing section but only outside one surface of the flat housing section. Further, the lens section of the housing is positioned alongside an edge of the flat housing section so that the lens section or a portion thereof can project to a level below or outside one of the flat housing section walls, whereby the optical lens axis or axes can be oriented for a xe2x80x9cside viewxe2x80x9d or a xe2x80x9cdown viewxe2x80x9d.
The advantages of the present transceiver are seen in that the positioning of the hemisphere or sphere permits substantially larger apertures for the lenses which are positioned in front of the emitter chip and in front of the detector chip. Larger lenses permit increasing the optical transmitter power and the optical receiver power which has the advantage that the transmission certainty and the transmission range are substantially increased compared to conventional transceivers. Due to the component arrangement according to the invention, the first housing section can have a flat parallelepiped shape which permits a symmetric arrangement of the terminals that define the above mentioned mounting plane, whereby the insertion of circuit elements and chips by an insertion automat is facilitated. The size of the present transceiver corresponds approximately to the size of an SO-8 housing (small outline with eight terminals). Yet, the transmission range is increased by a factor that is proportional to the square of the lens aperture surface sizes gained by the invention compared to the conventional lens aperture sizes in a housing of the same size as the present housing, Thus, no special housings are necessary for achieving the improved transmission range with the present transceiver.